In many medical procedures, X-ray live imaging of the patient is necessary to guide the operator. However, X-rays are well known to be carcinogenic and to induce various health damage. It is thus always desirable to minimize the exposure to X-rays, both for the patient and the operator. The X-ray dose delivered to the patient, for a specific type of X-ray machine, depends directly on the imaging time. It is the responsibility of the operator to minimize the exposure time by avoiding unnecessary imaging. As far as the operator is concerned, the problem is similar. There is obviously no need for the operator to be exposed and all measures are usually taken to reduce the X-rays dose on the operator and other members of the staff. Moreover, the staff is exposed to X-rays on a daily basis as opposed to the patient, who undergoes only sporadic exposure. Protection of the staff is thus regarded as a very important issue by health authorities.
In angioplasty procedures, X-ray imaging is typically performed with a machine that has an X-ray source on one side of the patient and a detector on the opposite side. The whole machinery can rotate and image the patient's body under various angles. When no patient is present between the source and the detector, most of the X-rays travel directly from the source to the detector. When the patient is present, part of the X-ray radiation still reaches the detector, where its intensity is recorded to compose the image delivered to the operator. However, in that case, a significant part (typically as high as 30%) of the X-rays are scattered by the patient's body and form what is commonly referred to as the secondary radiation. The secondary radiation is diffuse and may travel in all possible directions from the patient's body thus irradiating the surrounding staff.
Up to now, various devices have been used to screen the secondary radiation. These devices include rigid screens that can be slid over the patient, but also soft pads of various size and shape to be placed manually by the operator where required.
Radiation shielding placed directly on the patient can decrease scatter. One such shield is a small bismuth-based disposable shield (RADPAD, Worldwide Innovations and Technologies). When placed between the patient and the operator and outside of the primary beam, this shield can reduce operator doses by 44%. Meisinger et al., AJR:207, October 2016, 745-754. Small, lightweight disposable cloths with a 0.1-mm lead equivalency decreased scattered radiation to one-ninth to one-fifth of the original value with an increase overall patient entrance exposure rate of 30-40%, owing to compensating radiation beam adjustments made by the automatic exposure control. Id. Proper positioning is key, because placement of this or any high attenuation object in the path of the primary beam can markedly increase radiation to the patient through automatic exposure control. Id.
As the radiation is diffuse, the protective gear has to cover all possible radiation angles. In practice, this has been difficult to achieve, partly because the imaging machinery needs to move around the patient, and the operator needs to have unobstructed access to different parts of the patient. The above-mentioned free-standing protecting pads can be placed directly on the patient to fill the gaps. However, since the operator cannot see the X-ray secondary radiation that still leaks through the patchy barrier composed of those different devices, the operator does not always know how to place the free-standing pads or even which one to use. For example, one particular gap that has been spotted in recent studies is the region of the patient arm close to the operator. Kallinikou et al., Am J Cardiol. 118(2):1 88-94, 2016. A large amount of diffuse radiation leaks through the gap, and it is practically difficult to cover it due to its proximity to the edge of the table. Presently, a large radio-protective sheet for cardiology and angiology surgery does not exist on the market.
Thus, there is a need in the art for better radio-protection for the protection of operators. The invention fulfills this need.